Verify that the Plesk database is functioning before attempting to co…

…llaborate on any Plesk extensions

pleskdistup/actions/extensions.py

@@ -146,21 +146,28 @@ def __init__(self) -> None:
         self.ext_name = "tuxcare-els"
 
     def _is_required(self) -> bool:
-        # If database is not ready, we can't be sure about installed extensions
-        if (not plesk.is_plesk_database_ready()):
+        try:
+            return self.ext_name in dict(plesk.list_installed_extensions())
+        except plesk.PleskDatabaseIsDown:
+            # If database is not ready we will not be able to uninstall the extension anyway
+            log.warn("Mark the Tuxcare ELS extension uninstallation as unnecessary because the Plesk database isn't running")
             return False
 
-        return self.ext_name in dict(plesk.list_installed_extensions())
-
     def _prepare_action(self) -> action.ActionResult:
-        plesk.uninstall_extension(self.ext_name)
+        try:
+            plesk.uninstall_extension(self.ext_name)
+        except plesk.PleskDatabaseIsDown:
+            log.warn("Removing TuxCare ELS extension called when Plesk database is already down")
         return action.ActionResult()
 
     def _post_action(self) -> action.ActionResult:
         return action.ActionResult()
 
     def _revert_action(self) -> action.ActionResult:
-        plesk.install_extension(self.ext_name)
+        try:
+            plesk.install_extension(self.ext_name)
+        except plesk.PleskDatabaseIsDown:
+            log.warn("Re-installing TuxCare ELS extension called when Plesk database is still down")
         return action.ActionResult()
 
     def estimate_prepare_time(self) -> int:
@@ -233,13 +240,16 @@ def description(self, val: str) -> None:
         raise NotImplementedError
 
     def _do_check(self) -> bool:
-        extensions = dict(plesk.list_installed_extensions())
-        log.debug(f"Detected installed Plesk extensions: {extensions}")
+        try:
+            extensions = dict(plesk.list_installed_extensions())
+            log.debug(f"Detected installed Plesk extensions: {extensions}")
 
-        self.installed_violations = set(extension for extension in self.installed if extension not in extensions)
-        log.debug(f"Missing required extensions: {self.installed_violations}")
+            self.installed_violations = set(extension for extension in self.installed if extension not in extensions)
+            log.debug(f"Missing required extensions: {self.installed_violations}")
 
-        self.not_installed_violations = set(extension for extension in self.not_installed if extension in extensions)
-        log.debug(f"Installed conflicting extensions: {self.not_installed_violations}")
+            self.not_installed_violations = set(extension for extension in self.not_installed if extension in extensions)
+            log.debug(f"Installed conflicting extensions: {self.not_installed_violations}")
 
-        return not self.installed_violations and not self.not_installed_violations
+            return not self.installed_violations and not self.not_installed_violations
+        except plesk.PleskDatabaseIsDown:
+            return True

pleskdistup/actions/plesk.py

@@ -237,7 +237,12 @@ def name(self):
         return res
 
     def _prepare_action(self) -> action.ActionResult:
-        installed_extensions = set(ext[0] for ext in plesk.list_installed_extensions())
+        try:
+            installed_extensions = set(ext[0] for ext in plesk.list_installed_extensions())
+        except plesk.PleskDatabaseIsDown:
+            log.warn("Plesk database is down, can't retrieve installed extensions")
+            installed_extensions = set()
+
         log.debug(f"Currently installed extensions: {installed_extensions}")
         if installed_extensions:
             res_ext = installed_extensions
@@ -262,7 +267,10 @@ def estimate_prepare_time(self) -> int:
         if self.extensions_to_update is not None:
             extnum = len(self.extensions_to_update)
         else:
-            extnum = len(set(ext[0] for ext in plesk.list_installed_extensions()))
+            try:
+                extnum = len(set(ext[0] for ext in plesk.list_installed_extensions()))
+            except plesk.PleskDatabaseIsDown:
+                extnum = 0
         return 20 * extnum
 
     def estimate_post_time(self) -> int:

pleskdistup/common/src/plesk.py

@@ -114,6 +114,9 @@ def remove_conversion_flag(status_flag_path: str) -> None:
 
 
 def list_installed_extensions() -> typing.List[typing.Tuple[str, str]]:
+    if not is_plesk_database_ready():
+        raise PleskDatabaseIsDown("retrieving installed extensions")
+
     ext_info = subprocess.check_output(["/usr/sbin/plesk", "bin", "extension", "--list"], universal_newlines=True).splitlines()
     res: typing.List[typing.Tuple[str, str]] = []
     for line in ext_info:
@@ -124,10 +127,16 @@ def list_installed_extensions() -> typing.List[typing.Tuple[str, str]]:
 
 
 def install_extension(name: str) -> None:
+    if not is_plesk_database_ready():
+        raise PleskDatabaseIsDown(f"extension {name!r} installation")
+
     util.logged_check_call(["/usr/sbin/plesk", "bin", "extension", "--install", name])
 
 
 def uninstall_extension(name: str) -> None:
+    if not is_plesk_database_ready():
+        raise PleskDatabaseIsDown(f"extension {name!r} uninstallation")
+
     util.logged_check_call(["/usr/sbin/plesk", "bin", "extension", "--uninstall", name])
 
 
@@ -198,6 +207,12 @@ def list_installed_components() -> typing.Dict[str, PleskComponent]:
     return res
 
 
+class PleskDatabaseIsDown(Exception):
+    def __init__(self, message: str = ""):
+        self.message = f"Plesk database is not ready at: {message}"
+        super().__init__(self.message)
+
+
 def is_plesk_database_ready() -> bool:
     if mariadb.is_mariadb_installed():
         return systemd.is_service_active("mariadb")